scholarly journals A proof of four color conjecture (4CC)

Author(s):  
hongbo ZHUANG
Keyword(s):  

foundout a critical corresponding relationship between a δwheelof any maximal simple plane graph of n vertices(nMSPG)and its corresponding δcycleof a corresponding n-1MSPGof the nMSPG, and relied on theinductive way, while with the help of KempeChain (KC), this article gives a brand-newlogical proof for the famous and morethan 100 years old fourcolor conjecture (4CC).

2012 ◽  
Vol 21 (14) ◽  
pp. 1250129 ◽  
Author(s):  
SHUYA LIU ◽  
HEPING ZHANG

In this paper, we associate a plane graph G with an oriented link by replacing each vertex of G with a special oriented n-tangle diagram. It is shown that such an oriented link has the minimum genus over all orientations of its unoriented version if its associated plane graph G is 2-connected. As a result, the genera of a large family of unoriented links are determined by an explicit formula in terms of their component numbers and the degree sum of their associated plane graphs.


2013 ◽  
Vol 498 ◽  
pp. 76-99 ◽  
Author(s):  
Colin de la Higuera ◽  
Jean-Christophe Janodet ◽  
Émilie Samuel ◽  
Guillaume Damiand ◽  
Christine Solnon

2021 ◽  
Vol 28 (4) ◽  
Author(s):  
Marcus Schaefer

We show that a plane graph can be embedded with its vertices at arbitrarily assigned locations in the plane and at most $6n-1$ bends per edge. This improves and simplifies a classic result by Pach and Wenger. The proof extends to orthogonal drawings.


2013 ◽  
Vol 8 (8) ◽  
pp. 1030-1037
Author(s):  
Mingxin Li ◽  
Xiongfei Li ◽  
Jinfeng Zhang

2013 ◽  
Vol 23 (02) ◽  
pp. 75-92 ◽  
Author(s):  
ZACHARY ABEL ◽  
ERIK D. DEMAINE ◽  
MARTIN L. DEMAINE ◽  
SARAH EISENSTAT ◽  
JAYSON LYNCH ◽  
...  

We consider two types of folding applied to equilateral plane graph linkages. First, under continuous folding motions, we show how to reconfigure any linear equilateral tree (lying on a line) into a canonical configuration. By contrast, it is known that such reconfiguration is not always possible for linear (nonequilateral) trees and for (nonlinear) equilateral trees. Second, under instantaneous folding motions, we show that an equilateral plane graph has a noncrossing linear folded state if and only if it is bipartite. Furthermore, we show that the equilateral constraint is necessary for this result, by proving that it is strongly NP-complete to decide whether a (nonequilateral) plane graph has a linear folded state. Equivalently, we show strong NP-completeness of deciding whether an abstract metric polyhedral complex with one central vertex has a noncrossing flat folded state. By contrast, the analogous problem for a polyhedral manifold with one central vertex (single-vertex origami) is only weakly NP-complete.


1975 ◽  
Vol s2-12 (1) ◽  
pp. 59-66 ◽  
Author(s):  
R. J. Faudree ◽  
R. H. Schelp
Keyword(s):  

1976 ◽  
Vol 16 (3) ◽  
pp. 233-239 ◽  
Author(s):  
Arthur M. Hobbs ◽  
John Mitchem
Keyword(s):  

2010 ◽  
Vol 411 (44-46) ◽  
pp. 3979-3993
Author(s):  
Shunsuke Ota ◽  
Ehab Morsy ◽  
Hiroshi Nagamochi

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